1. Field of the Invention
The present invention relates to a suspension board with a circuit, a suspension board assembly sheet with a circuit and a method of manufacturing the suspension board with a circuit and the suspension board assembly sheet with a circuit.
2. Description of Related Art
Actuators are used in drives such as hard disc drives. Such an actuator includes an arm provided rotatably around a rotation shaft, and a suspension board with a circuit for a magnetic head that is attached to the arm. The suspension board with a circuit is a printed circuit board for positioning the magnetic head at a desired track of a magnetic disc.
Generally, in the suspension board with a circuit, a wiring is formed at one surface, and a metal substrate is formed at another surface, of an insulating layer. In a suspension described in JP 2012-119032 A, a plurality of conductors are formed at the upper surface of the insulating layer, and a metal base is formed at the lower surface of the insulating layer. An electrical circuit portion that is electrically independent from the metal base is formed at the lower surface of the insulating layer. End portions of part of the plurality of conductors are connected to the electrical circuit portion via a conductor coupling portion that penetrates the insulating layer.